# Test and Measurement World

## Test and Measurement World Terminology Section

One Stop For Your Test and Measurement Need

Introduction:
As we know multimeters are of two types viz. analog multimeter and digital multimeter(DMM). Voltage, current and resistance are the most fundamental parameters used in electricity and electronic circuits. Electricity through conductor is like flowing of water through pipe. Like every pipe has certain applied pressure which causes flow of water.

In electronic circuit, voltage is applied to the circuit using generator/battery/solar panel. This causes current flow in the conductor. Any obstruction to the flow of current is known as resistance.

Voltage (V) is measured in volts, current (I) in amp and resistance (R) in ohms. There are two types of power sources viz. AC (Alternating Current) and DC (Direct Current).

As shown in the figure-1, analog multimeters use needle on calibrated scale to indicate the measurement of parameters (V,I,R) as per AC or DC source. Analog Multimeter should be appropriately set to measure AC or DC values. Every voltmeter or multimeter of analog type has internal resistance which is expressed in "Ohms/Volt".

Probes are connected at respective terminals as per measurement to be made. For current measurement analog multimeter is connected in series while for voltage measurement it is connected in parallel.

### Benefits or advantages of Analog Multimeter

Following are the benefits or advantages of Analog Multimeter:
➨They are cheaper compare to digital meters.
➨They respond very quickly to measurement.
➨They do not require batteries unless resistance needs to be measured.

### Drawbacks or disadvantages of Analog Multimeter

Following are the disadvantages of Analog Multimeter:
➨It requires manual reading of parameters from the scale which is cumbersome unlike digital multimeter.
➨The results are not accurate unlike DMM. The inaccurate results are caused due to three types of errors viz. improper range setting, improper counting on the scale, wrong setting on AC/DC.

➨The meter uses needle which is rotated by magnetic field. It gets damage if meter gets dropped by mistake.
➨Analogmultimeter does not have any digital circuitry. Hence it can not perform advanced measurements such as frequency, impedance, waveform analysis etc. which are commonly measured by digital multimeter.